Electrical interfaces are usually formed with a pair, or multiple pairs, of opposing spaced-apart surfaces which are electrically connected when the circuit is closed. The surfaces may be brought into direct contact with one another or there may be an intermediate connector means between the opposing surfaces.
In a variety of product applications, the prior art has used compressible electrical connectors which are well known in the electronic industry. These compressible electrical connectors include a plurality of closely-pitched conductive circuit elements or traces photographically etched or otherwise formed on a flexible film which is bonded to an elastomeric core or other suitable carrier. Under the trademark "AMPLIFLEX", AMP Incorporated of Harrisburg, Pa., supplies a wide variety of such compressible electrical connectors to the electronic and aerospace industries.
The effectiveness of the electrical interface between the conductive elements on compressible connector and the surface on the circuit element which is contacted is dependent upon several factors. One of these factors is the materials which are in direct contact such as the metals or metallic platings of silver, copper, nickel, tin, gold, etc. Another factor is the compressibility and resiliency of the elastomeric core. A third factor is the nature of the physical contact which is made between conductive elements and the respective surfaces.
With respect to the latter factor, when the physical contact is between relatively smooth and uniform metals, the electrical connection is frequently unsatisfactory. This electrical contact is frequently degraded by the presence of dirt or dust at the contact interface. Another commonly occurring problem is oxidation of one or both of the metal contact surfaces which seriously degrades the efficiency and reliability of the electrical contact.
It is important therefore, to have a reliable electrical connection between the interfacing surfaces to assure a reproducible and complete electrical circuit even in the presence of dirt and oxidized metallic surfaces.